The present invention relates to a method of making a hybrid structure, such as e.g. a dashboard support, in combined steel-plastic construction, as well as to such a hybrid structure.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
Current passenger cars use dashboard supports as supporting structure, with the dashboard supports satisfying different cockpit functions. The dashboard support has a cross member which extends from a driver-side A pillar to a passenger-side A pillar and reinforces the vehicle body. Cross members are typically made from one or more tubes, profiled cross sections, or pressed shells. Various mounts or castings are hereby joined to the cross member to provide, for example, mountings for the longitudinal column as well as receptacles for airbags. A cross member is normally provided with holes, stampings, and bends, but still has to meet crash, static, and vibration standards, despite its complex configuration.
German Offenlegungsschrift DE 103 46 097 A1 discloses dashboards supports made in composite construction, e.g. by injection molding plastic parts to steel tubes. Polypropylene or polyamide are mostly used as plastic in this construction, with the actual connection between the cross member and the molded-on plastic structure being established by a form fit. As a result, the plastic part is normally enveloping and/or molded around to the steel tube. More current approaches suggest to coat the metal components so as to realize a material union between the metal and the plastic components.
A drawback of molding-on plastic components is the accompanying deformation of the metal component as a result of the high injection pressures. Thus, the reduction of the wall thickness desired for reasons of weight savings for steel tubes, profiled cross sections or pressed shells is possible only to a limited degree.
It would therefore be desirable and advantageous to provide an improved method of making a hybrid structure and an improved hybrid structure to obviate prior art shortcomings and to allow to mold injection-molded parts to the outer surfaces of a tube component, with the wall thickness of the tube component being reduced sufficient to be able to make a defined connection which can be implemented between the tube component and the molded-on injection-molded part, despite stress caused by the injection pressure.